Not all of the blasts were supposed to be big. This one yielded about 80 times less energy than the bomb that exploded over Hiroshima. https://gfycat.com/gifs/detail/possibleinborndogwoodclubgall That may be the most provocative of them all today. What would be the response to a nuclear power using one of these in combat? Escalation? Retaliation in kind? The damage to the surrounding environment could be small, espec…
In short, for much of the Cold War the USSR had such a numbers advantage over NATO when it came to tank forces that the only chance NATO had to hold off a full-scale tank invasion by the USSR would have been the use of tactical nukes.
As you rightly point out, MAD strategy doesn't quite apply here. Yes, the Davy Crockett is a nuclear weapon. However, the fact that it only would've leveled the playing field probably means that the USSR wouldn't have immediately responded in kind. That said, a world of tactical nukes is definitely a scary one (Frank Herbert was rather prescient in this regard), and I'm glad we've never had to find out what it would look like.